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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>38.4. User-defined Procedures</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="xfunc.html" title="38.3. User-defined Functions" /><link rel="next" href="xfunc-sql.html" title="38.5. Query Language (SQL) Functions" /></head><body><div xmlns="http://www.w3.org/TR/xhtml1/transitional" class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">38.4. User-defined Procedures</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="xfunc.html" title="38.3. User-defined Functions">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="extend.html" title="Chapter 38. Extending SQL">Up</a></td><th width="60%" align="center">Chapter 38. Extending <acronym xmlns="http://www.w3.org/1999/xhtml" class="acronym">SQL</acronym></th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 11.5 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="xfunc-sql.html" title="38.5. Query Language (SQL) Functions">Next</a></td></tr></table><hr></hr></div><div class="sect1" id="XPROC"><div class="titlepage"><div><div><h2 class="title" style="clear: both">38.4. User-defined Procedures</h2></div></div></div><a id="id-1.8.3.7.2" class="indexterm"></a><p>
A procedure is a database object similar to a function. The difference is
that a procedure does not return a value, so there is no return type
declaration. While a function is called as part of a query or DML
command, a procedure is called explicitly using
the <a class="xref" href="sql-call.html" title="CALL"><span class="refentrytitle">CALL</span></a> statement.
</p><p>
The explanations on how to define user-defined functions in the rest of
this chapter apply to procedures as well, except that
the <a class="xref" href="sql-createprocedure.html" title="CREATE PROCEDURE"><span class="refentrytitle">CREATE PROCEDURE</span></a> command is used instead, there is
no return type, and some other features such as strictness don't apply.
</p><p>
Collectively, functions and procedures are also known
as <em class="firstterm">routines</em><a id="id-1.8.3.7.5.2" class="indexterm"></a>.
There are commands such as <a class="xref" href="sql-alterroutine.html" title="ALTER ROUTINE"><span class="refentrytitle">ALTER ROUTINE</span></a>
and <a class="xref" href="sql-droproutine.html" title="DROP ROUTINE"><span class="refentrytitle">DROP ROUTINE</span></a> that can operate on functions and
procedures without having to know which kind it is. Note, however, that
there is no <code class="literal">CREATE ROUTINE</code> command.
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